As an electronic apparatus such as an electronic timepiece having a function for receiving wireless information, there is known, for example, a radio wave clock for receiving time information transmitted by wireless (standard radio waves) and performing time correction. Such a radio wave clock is normally driven by a battery, but since power is consumed in receiving radio waves, the size of the battery is increased compared with that of a normal clock, and there is a problem of requiring more often replacement of the battery. Further, there is a problem that its movement is also enlarged.
Because of this, a radio wave clock having a solar power-generation mechanism installed as a generating mechanism is known (for example, Japanese Unexamined Patent Application Publication No. 11-160464).
The radio wave clock having the solar power-generation mechanism includes a solar battery as the solar power-generation mechanism, a receiving mechanism having an antenna for receiving standard radio waves, and a time-measuring mechanism for measuring time, and the time of the time-measuring mechanism is corrected according to the standard radio waves received by the antenna.
By such a structure, the time-measuring mechanism and the receiving mechanism can be driven by using the power generated by the solar power generation mechanism. Therefore, only if the solar battery generates power and is charged by solar light, can it be used as a radio wave clock driven semi-permanently.
However, efficient solar power generation cannot be assured since it is dependent on conditions such as daylight amount (for example, cloudy or rainy weather), seasons (for example, winter), and regions (for example, high latitude region), and so it sometimes cannot supply power. The radio wave clock needs a large amount of power since the received time information should be processed (amplification, demodulation) by the receiving mechanism. Because of this, if sufficient power is not supplied to the receiving mechanism, the standard radio waves cannot be received, or the standard radio waves are wrong-received, and therfore the receiving sensitivity of the receiving mechanism is decreased. Further, there is a problem that rapid charge is impossible in the solar battery if a receiving light energy is weak.
Because of this, the radio wave clock having the solar power-generation mechanism is not necessarily a convenient clock.
Therefore, the inventor of the present invention studied a method of installing a power-generation mechanism inside a radio wave clock, for converting mechanical energy to electrical energy. The power-generation mechanism for converting mechanical energy to electrical energy includes, for example, a winding stem for inputting mechanical energy from the outside and a generator for converting the mechanical energy from the winding stem to electrical energy. The generator includes a rotor that is rotated by the mechanical energy and a generating coil that generates electrical energy from the change of magnetic flux that accompanies the rotation of the rotor. By using such a structure, for example, if mechanical energy is input by the method of rotating the winding stem, etc., the power generation can be performed whenever necessary. Therefore, compared with the solar power generation, method, since in the present method power generation is possible regardless of the conditions of seasons, daylight amount, regions, etc., the present method provides an advantage that rapid power generation can be much easily performed.
However, when power generation occurs by use of the generating coil, a magnetic field is generated by the generating coil. An antenna is affected by the magnetic field generated by the generating coil with standard radio waves. Therefore, when standard radio waves are received by the antenna, if the magnetic field from the generating coil overlaps the antenna, the signal of the standard radio waves is deformed by the influence of the magnetic field, the standard radio waves cannot be received or are wrong-received. That is, if a power-generation mechanism for converting mechanical energy to electrical energy is just simply installed inside the radio wave clock, there occurs a new problem that standard radio waves cannot be received.
Such a problem is not limited to an electronic timepiece having a radio wave correction function, and is a common problem which can be applied to various electronic apparatuses including a power-generation mechanism for converting mechanical energy to electrical energy and an antenna receiving wireless information from the outside.
Therefore, in a configuration of the radio wave clock, it is necessary to install a battery having storage capacitance enough to supply the power consumed by the receiving operation, the receiving antenna, or the receiving circuit further to a time-measuring mechanism or an electromagnetic motor. In a portable electronic timepiece such as a wristwatch, the thickness is required to be as thin as possible to improve the installation or design characteristics, and the thin thickness is required in a radio wave clock having a receiving antenna.
As a structure for the radio wave clock having a thin thickness, Japanese Unexamined Patent Application Publication No. 2000-105285 discloses a structure in which the antenna is disposed on almost the same section with a module for performing the function as a portable electronic timepiece. Also, Japanese Unexamined Patent Application Publication No. 11-64547 discloses a structure in which an antenna core is extended along the end of a print circuit substrate in the placement of the antenna core and the electronic module circuit substrate. However, since the components for the module and the placement with the antenna are not disclosed, it is difficult to make the radio wave clock thin.
An object of the present invention is to solve the problem as above, and to provide an electronic timepiece and an electronic apparatus being capable of receiving wireless information from the outside with a power-generation mechanism therein.
Another object of the present invention is to provide an electronic timepiece capable of receiving wireless information from the outside with a thin thickness and a small size.